1. Field
The subject apparatus is in the field of hand tools, specifically tools used on the end of a handle. More specifically it is in the field of such tools used in drywall construction for finishing the joints between panels of plasterboard. Still more specifically it is in the field of flat finishing boxes used to dispense a compound, termed mud in the trade, onto the joints and provide a smooth, specifically contoured surface.
2. Prior Art
There is prior art in this field known to the subject inventor and relating to flat finishing boxes as such.
U.S. Pat. No. 2,889,699, issued to Ames, shows a flat finishing box (mastic applicator having interchangeable heads); however, the interchangeable heads comprise one for applying mastic (known as mud in the trade) in corners and the other for use on flat joints between plasterboard panels. There are no provisions for applying the mud in any of three swath widths from a single box. As is well known in the art, commercially available finishing boxes are made in three widths. The narrowest boxes dispense mud in a swath 7 inches wide; the medium width boxes dispense in a swath width of 10 inches and the widest boxes provide a swath 12 inches wide. A box is filled with mud and used until refilling is required. In use a box is attached to the end of a special handle by which it is held against and moved along a joint. It is common procedure to first cover a joint with a 7 inch swath, a 10" swath and finally a 12" swath, although the 10" or 12" swaths may be omitted under certain circumstances. Each swath requires a volume of mud per foot of joint or swath length. Because the 7" swath is applied first, the volume per foot for the 7" width is greater than for the 10" and 12" widths. This fact, coupled with the fact that the box for the 7" width has the least mud capacity of the three boxes, makes it necessary to refill the 7" box most frequently. In order to apply swaths in sequence as described it is necessary to have boxes of the various widths and handles for each or, if not, change handles from box to box. In any case, it is well known that at any given time on a job, approximately two out of three boxes are partially filled with mud and idle and time is used changing handles from box to box.
In view of the above the objectives of the subject invention are to reduce the frequency of refilling boxes providing 7" wide swaths, reduce the number of idle, partially filled boxes, reduce the number of boxes needed to provide a given work capacity, and either reduce the frequency of the need to change handles from box to box or the number of handles required for given work capacity. In other words, the prime objective is to provide a flat finishing box from which mud can be dispensed in any of plurality of swath widths depending on the head attached to the box.